The Colorado River's Horseshoe Bend in Page, Ariz., is shown on March 5, 2008. FILE PHOTO: THE ASSOCIATED PRESS

Demand for water from the Colorado River could vastly outstrip supply in coming decades, as populations that depend on it grow by nearly 40 million, according to a report released Wednesday by the U.S. Department of the Interior.

Climate change is expected to further reduce supplies along the river, a significant source of imported water for Orange County and the rest of Southern California.

The study projects supply and demand over the next 50 years and lists some 150 solutions proposed by study participants or the public – from the exotic and unlikely, such as towing icebergs from the Arctic, to the more familiar, including increased conservation, desalination and vegetation control.

"Demand is going to grow," Interior Secretary Ken Salazar told reporters Wednesday. "We're also going to see a decline in water supply on the Colorado River basin. That is what all the science is telling us."

Without some kind of intervention, demand could outweigh supply by some 3.2 million acre-feet on average by 2060, the report says.

And the 40 million people in the seven-state Colorado River basin could swell to some 76.5 million under a "rapid growth" scenario envisioned in the report.

Users include 22 Native American tribes and a number of national parks and wildlife refuges; river water irrigates some four million acres of land and provides 4,200 megawatts of hydroelectric power.

The study was authorized by Congress in 2009, and was conducted by the Bureau of Reclamation and the seven states in the river basin: Arizona, California, Colorado, New Mexico, Nevada, Utah and Wyoming.

Orange County's share

About half of Orange County's water is imported, the rest coming from the county's deep aquifer, according to the Municipal Water District of Orange County. And about half of the imported water comes from the Colorado.

And the Colorado supply is dwindling.

"The Colorado River basin experienced 12 years of drought," Anne Castle, the Interior's assistant secretary for water and science, told reporters. "And the problem of drier climate throughout The Colorado River basin is one that we simply have to tackle now, so that our children and grandchildren will have adequate supplies of water in the future."

A separate report projected a 9 percent reduction in Colorado River water over the next 50 years because of climate change alone, Salazar said.

The new report does not attempt to choose among the long list of proposed solutions, though Salazar labeled several, including movement of icebergs or importation from the Missouri River, as "impractical and not feasible."

Reducing demand for river water

But he considered a number of others within reach, among them control of vegetation, such as tamarisk, to reduce its water consumption along the river, stepped-up conservation in cities and on farms, water transfers and desalination projects.

California has taken steps to reduce its demand on the Colorado, said a statement from Jeff Kightlinger, general manager of Southern California's water wholesaler, the Metropolitan Water District in Los Angeles.

They include water conservation measures, increased agricultural efficiency and a MWD program to store water in Lake Mead – all reducing the state's river consumption by 500,000 acre-feet since 2003.

Southern California historically has drawn about a third of its water from the Colorado; MWD's supply, which is passed on to downstream agencies, has varied from 40 to 60 percent, with the rest coming from Northern California through the State Water Project, said MWD spokesman Bob Muir.

User Agreement

Keep it civil and stay on topic. No profanity, vulgarity, racial
slurs or personal attacks. People who harass others or joke about
tragedies will be blocked. By posting your comment, you agree to
allow Orange County Register Communications, Inc. the right to
republish your name and comment in additional Register publications
without any notification or payment.